Blue and UV combined photolithographic polymerization for the patterning of thick structures

• Combining two photopolymerization processes, we obtained double layered materials.
• The reactions were optimized varying the photoinitiator and the irradiation time.
• The use of different wavelengths allows to accurately control the curing processes.
• The formation of thick patterned structures are achieved.
• The method is suitable for the fabrication of multi-polymeric patterned structure.

This work proposes the realization of a thick multi-layer patterned structure using a photolithographic technique which combines two photopolymerization processes and two different wavelengths: UV and visible light. Multilayer structures are constructed by a simultaneous curing and bonding of layers of different materials after casting immiscible resins in one step and let them stratifying in the mold. The use of two different wavelengths allows the fabrication of patterned structures formed by two different materials, i.e. a siloxane acrylic layer superimposed and strongly adherent onto an epoxy layer. The optimization of the two reactions was done varying the photoinitiator systems, the irradiation time and selecting the right wavelength.